Peripheral arterial disease (PAD) is a disease in which plaque builds up in the arteries that carry blood to a subject's head, organs, and limbs. Plaque is made up of fat, cholesterol, calcium, fibrous tissue, and other substances in the blood. Over time, plaque hardens and narrows the subject's arteries. This limits the flow of oxygen-rich blood to the subject's organs and other parts of the body. When plaque builds up in the body's arteries, the condition is called atherosclerosis. Atherosclerosis (also known as arteriosclerotic vascular disease or ASVD) is a condition in which an artery wall thickens. This condition is commonly referred to as a hardening or furring of the arteries.
Atherosclerosis can affect any artery in the patient's vascular system, including arteries in the heart, brain, arms, legs, pelvis, and kidneys. As a result, diseases other than PAD, may develop based on which arteries are affected. For example, coronary heart disease (CHD), also called coronary artery disease occurs when plaque builds up in the coronary arteries, thereby narrowing the coronary arteries and reducing blood flow to the heart muscle. If blood flow to the heart is reduced or blocked, the subject may incur chest pain or discomfort or a heart attack. Carotid artery disease occurs if plaque builds up in the arteries on each side of a subject's neck (the carotid arteries), which supply oxygen-rich blood to the brain. If blood flow to the brain is reduced or blocked, the subject may have a stroke. Chronic kidney disease can occur if plaque builds up in the renal arteries, which supply oxygen-rich blood to the kidneys. Accordingly, chronic kidney disease may cause a gradual loss of kidney function.
A variety of options, including surgery, exist for treating atherosclerosis. One such surgical option is atherectomy, which is a minimally invasive surgical procedure for removing plaque from the blood vessel (e.g., artery, vein, vein graft) with a catheter. The catheter generally has a working tip, such as a sharp blade to cut the plaque or a laser to ablate the plaque. These catheters, particularly, the sharp bladed catheter, may also be designed to collect the cut plaque in a chamber its tip, thereby allowing the plaque to be removed as the device is removed from the blood vessel. Examples of such mechanical cutting atherectomy catheters may include those illustrated and discussed in U.S. Publication Nos. 2008/0154293 and 2008/0154296 both of which are incorporated herein by this reference in their entirety.
Additionally, examples of laser ablation atherectomy catheters may include in U.S. Pat. Nos. 5,456,680 and 5,643,251 both of which are incorporated herein by this reference in their entirety. Furthermore, Spectranetics Corporation, the assignee of this disclosure, sells a coronary laser atherectomy catheter under the trade name ELCA™ and a laser ablation under the trade name Turbo Elite™, which is used to treat PAD, particularly above and below the knee. Laser catheters, such as these, have a plurality of laser emitters at its distal tip. The catheters may also have a central passageway or lumen which receives a guidewire. The guidewire is typically inserted into the blood vessel prior to catheter introduction and traverses the occlusion. Once the guidewire is inserted, it facilitates the advancement and placement of the catheter to the selected portion(s) of the blood vessel for laser ablation of plaque.